Research and control of SRG for variable-speed wind energy applications

Based on the investigation of the actual behaviour of switched reluctance generator (SRG), the nonlinear mathematical models of SRG are established, and the characteristics of its output voltage ripples are simply analyzed. Accordingly, a control system of voltage feedback with angles position controller (APC) section and filtering section is proposed to suppress voltage ripples. By choosing proper control parameters the stability of the whole system can be guaranteed for variable-speed. In the medium and low speed range, voltage ripples can be reduced effectively by closed loop control of voltage. For high speeds, the voltage feedback control is failed when winding current becomes single pulse mode and the proposed APC part is actuated automatically. The turn-on angle and turn-off angle are dynamically shifted to assist voltage feedback regulation control. The filtering components are properly designed to minimize high-frequency ripples caused by commutation and pulse width modulation (PWM) switching. With the compensating action of APC part and the filtering function, more desirable static and dynamic performances of SRG can be obtained. The effectiveness of the control approaches is confirmed by simulation results.